In recent years microcantilever structures have gained wide acceptance for use as physical, chemical and biological sensors. Such sensors consist of a silicon or poly silicon beam coated with a substance that activates the surface such that it will absorb the material to be sensed. As the target material is absorbed, the mass, and thus the resonant bending or vibrational frequency, of the beam changes signaling the material's presence. Generally, due to practical limitations, only a lone analyte or group of analytes can be detected through this approach. Arrays of isolated oscillators, individually functionalized to detect different analytes, can be used to broaden detection capabilities. However, the inherent complexity of such arrays limits their utility.
Description of Technology
The Single Input - Single Output (SISO) Sensor consists of a number (n) of functionalized, frequency-mistuned microbeam resonators connected to a common shuttle mass, which is used for both actuation and sensing. Given vibration localization in the set of mistuned oscillators, the shuttle mass itself can be used to track resonance shifts in the individual microbeams. This structure can, in principal, be used to detect any type, number and combination of analytes, producing an equal result to that of an array of individual sensors. However, the SISO sensor is considerably less complex since there is only one input and one output needed to control n sensors. This allows for the building of SISO structures that will be much smaller and simpler than the aggregate of n standard microbeam sensors, and therefore less expensive.
- Reduced size/cost: The sensor uses a single input and single output to actuate the resonant vibrations and sense frequency shifts associated with detection. This reduced complexity leads to smaller size and simpler electronics resulting in lower overall cost.
- Highly manufacturable: Employs the standard Micro-Electro-Mechanical Systems (MEMS) technology used in the fabrication of conventional single analyte microcantilever structures.
- High sensitivity: Comparable to individual microcantilever sensors.
- Fast response: Identical to individual microcantilever sensors.
- Low power consumption: Identical to individual microcantilever sensors.
Applications are identical to those addressed by conventional sensor arrays, including: healthcare (PSA and LDL screening), biomedical (gene sequencing), military (explosives detection), homeland security (biotoxin detection), and environmental monitoring (herbicide or heavy metal detection).
1 U.S. patent issued: 7,584,649
Jeffrey Rhoads, Steven Shaw, Barry DeMartini, Kimberly Turner